The objectives of the proposed research are concerned with a comprehensive study of kidney disease in childhood. The studies will attempt to define the pathogenesis of diffuse glomerular disease -including immune mediated glomerulonephritis and nephrotic syndrome; to dissect the various forms of kidney disease by detailed morphologic, immunopathologic and complement studies; to define the biologic role of the mesangium and the relationship of the glomerular filter to lymphocyte mediators and the glomerular polyanion.